Hi tejun On 09/11/2018 09:44 PM, Tejun Heo wrote: > Hello, > > On Tue, Sep 11, 2018 at 12:40:36PM +0800, jianchao.wang wrote: >> (long)(sum (every cpu's refcounter)) + atomic refcounter >> >> and when switch to atomic mode, there could be value left in atomic refcounter. >> then the unsigned long percpu refcounter cound be decreased from 0. > > It can always do that. Imagine a task getting a ref on one cpu, > migrating and putting it on another. The only thing which matters is > that the sum of everything adds upto what it should be. > Thanks for your kindly response. I have got the point here. Thanks Jianchao
